1. Field of the Invention
The field of art to which this invention pertains is the solid bed adsorptive separation of fatty acids. More specifically the invention relates to a process for separating an unsaturated fatty acid comprising a monoethanoid fatty acid from a diethanoid fatty acid which process employs an adsorbent comprising particular polymers which selectively adsorbs a monoethanoid fatty acid from a feed mixture containing a monoethanoid fatty acid and a diethanoid fatty acid.
2. Description of the Prior Art
It is known in the separation art that certain crystalline aluminosilicates can be used to separate certain esters of fatty acids from mixtures thereof. For example, in U.S. Pat. Nos. 4,048,205; 4,049,688 and 4,066,677 there are claimed processes for the separation of esters of fatty acids of various degrees of unsaturation from mixtures of esters of saturated and unsaturated fatty acids. These processes use adsorbents comprising an X or a Y zeolite containing a selected cation at the exchangeable cationic sites.
In contrast, this invention relates to the separation of certain fatty acids rather than fatty acid esters. We have discovered that adsorbents comprising hydrophobic insoluble crosslinked polystyrene polymers exhibit adsorptive selectivity for a monoethanoid fatty acid with respect to diethanoid fatty acid thereby making separation of such fatty acids by solid bed selective adsorption possible. In a specific embodiment our process is a process for separating a monoethanoid unsaturated fatty acid having 18 carbon atoms per molecule (oleic acid) from a mixture comprising that fatty acid and a diethanoid fatty acid having 18 carbon atoms per molecule (linoleic acid). Substantial uses of fatty acids are in the plasticizer and surface active agent fields. Derivatives of fatty acids are of value in compounding lubricating oil, as a lubricant for the textile and molding trade, in special lacquers, as a water-proofing agent, in the cosmetic and pharmaceutical fields, and in biodegradable detergents.